The man who helped make the bombs that killed 20 people - including four Australians - has refused to apologise for his role in the 2005 terror attacks.

Convicted Bali bomb-maker Muhammad Cholili was released on parole on Wednesday after serving less than half of his 18-year sentence when he was found guilty of helping slain ringleaders Noordin Mohammad Top and Azahari Husin assemble the explosives in September 2006.

'I will not apologise to Australian [victims] because I didn't involve in second Bali bombing [sic],” he told Nine News.

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Convicted terrorist Mohammad Cholili was released from Lowokwaru Prison in Malang, East Java, Indonesia on Wednesday

'My role was simply hiding Dr. Azahari [one of the Bali bombing masterminds], but I have never involved in second Bali bombing [sic].'

The attacks on restaurants also injured more than 100 people on October 1, 2005.

Corrections directorate-general Ika Yusanti said Cholili had been eligible for parole since April for his favourable record during his time in prison.

'My case is different with other cases,' Cholili told reporters.

'I’ve been released on parole for good behaviour. I’m happy I’m free.'

Cholili served a eight-year sentence for his involvement in a bombing in Bali on October 1, 2005

Sentenced to 18 years for his involvement in the bombing, his sentence was reduced for good behaviour

Cholili's associates Noordin and Azahari were key members of the Al-Qaeda-linked Jemaah Islamiyah extremist network blamed for a string of deadly attacks in Indonesia, including the 2002 Bali bombing which killed 202 people, mostly Western holidaymakers.

'Muhammad Cholili has been released on parole today after several remissions which he received for good behaviour. He has never broken any prison regulations,' Ms Yusanti told AFP.

Sentences are routinely cut in Indonesia to mark major religious celebrations such as Eid al-Fitr Muslim holiday and the country's independence day on August 17.

This meant that Cholili served less than half of his term, but Yusanti said the convicted bomb-maker's release had 'received the recommendation from the Detachment 88 and the National Anti-Terror Agency', which are responsible for tracking terror activities in the country.

Cholili was sentenced in September 2006 for his part in assisting the ringleaders of the bombing

The bombings killed 20 people - including four Australians - and injured more than 100

The blast went off in restaurants in Kuta, Bali, on October 1, 2005

Ms Yusanti also added that the authorities would continue to monitor Cholili's activities and he will not be able to leave Indonesia without the justice minister's approval.

'If he commits any crime or creates any problems in the community, he will be sent back to prison,' she added.

Indonesia's English daily The Jakarta Globe reported that Cholili was surprised to learn of his release from the Lowokwaru Prison in Malang, East Java, but was happy to leave prison.

'The most important thing is to go home and meet my family,' he was quoted as saying by the newspaper.

Indonesia, the world's biggest Muslim-majority nation, has long struggled with terrorism but a successful clampdown in recent years has prevented major deadly attacks.

However, recent reports of Indonesians joining the procession of jihadists to Syria and Iraq have sparked fears that they will revive sophisticated militant networks.